Gaining New Understanding of Sarcomere Length Nonuniformities in Skeletal Muscles

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dc.contributor.advisorHerzog, Walter
dc.contributor.authorLi, Meng
dc.contributor.committeememberSyme, Douglas
dc.contributor.committeememberJoumaa, Venus
dc.date2023-09
dc.date.accessioned2023-09-29T19:21:04Z
dc.date.available2023-09-29T19:21:04Z
dc.date.issued2023-09-28
dc.description.abstractSarcomere lengths are non-uniform on all structural levels of mammalian skeletal muscle. These non-uniformities have been associated with a variety of mechanical properties, including residual force enhancement and depression, creep, increased force capacity, and extension of the plateau of the force-length relationship. However, the nature of sarcomere length non-uniformities has not been explored systematically. The purpose of this study was to determine the properties of sarcomere length non-uniformities in active and passive muscle. Single myofibrils of rabbit psoas (n=20; with 412 individual sarcomeres) were subjected to three activation/deactivation cycles at short, intermediate, and long sarcomere lengths of 2.7, 3.2, and 3.6 µm respectively, and individual sarcomere lengths were measured at 4 passive and 3 active points during the activation/deactivation cycles. The primary results were that sarcomere length non-uniformities did not occur randomly but were governed by some structural and/or contractile properties of the sarcomeres and that sarcomere length non-uniformities differed greatly between the active and passive state. We propose that the mechanisms that govern the systematic sarcomere lengths non-uniformities observed in active and passive muscle are associated with the variable number of contractile proteins and the variable number and stiffness of titin filaments in individual sarcomeres.
dc.identifier.citationLi, M. (2023). Gaining new understanding of sarcomere length nonuniformities in skeletal muscles (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.urihttps://hdl.handle.net/1880/117303
dc.identifier.urihttps://doi.org/10.11575/PRISM/42145
dc.language.isoen
dc.publisher.facultyGraduate Studies
dc.publisher.institutionUniversity of Calgary
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectSarcomere length non-uniformity
dc.subjectsarcomere contraction dynamics
dc.subjectpassive structures
dc.subjectcross-bridges
dc.subjectmyofibrils
dc.subjectskeletal muscle properties
dc.subject.classificationAnimal Physiology
dc.titleGaining New Understanding of Sarcomere Length Nonuniformities in Skeletal Muscles
dc.typemaster thesis
thesis.degree.disciplineKinesiology
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameMaster of Science (MSc)
ucalgary.thesis.accesssetbystudentI do not require a thesis withhold – my thesis will have open access and can be viewed and downloaded publicly as soon as possible.
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